1. Field of the Art
The present invention relates to dietary lipid digestion-absorption inhibitory agents and ingesta which are expected to have a dietary lipid absorption inhibitory effect, an obesity preventing effect and the like.
2. Related Art
In recent years, intake of lipid is increasing with the improvement or westernizing of the eating habits in Japan. According to the report of the "National Nutrition Survey" conducted (in Japan) in the year of 1989, the ratio of caloric intake from lipid is in excess of 25% on an average, and this ratio is already in a danger zone. Such a constant excessive ingestion of lipid causes the problem of obesity, and a variety of its complications, for instance, heart or circulatory diseases, respiratory diseases, diabetes and the like, are becoming even an object of public concern in developed countries.
For this reason, the approaches aiming at removal of body fat or lowering of dietary lipid are now being actively made in many countries, and a variety of methods, medicines and commodities as described below have been proposed.
First of all, the intake of lipid can be restricted by alimentotherapy, fat substitutes, or anotectic agents. Alimentotherapy is, however, attended with great difficulties when it is practiced for a prolonged period of time, because this therapy often adopts an excessively restricted diet, whereas lipid-rich tasty foods are abundant in our present-day life. With respect to fat substitutes, a great variety of commodities such as substitutes having a carbohydrate base, a protein base or an oils and fats base, and synthetic fat substitutes have been developed. However, it is not easy with such substitutes to satisfy present-day people, who tend to pursue natural taste and genuine relish. On the other hand, there is a method in which only a feeling of plenitude is obtained by taking konjak mannan or the like, thereby diminishing appetite itself. Such a method is however accepted only by a very few obesity patients because konjak mannan cannot be readily ingested due to their physical properties. Further, mazindol, fenfluramine and the like have been known as anorectic agents. However, these medicines can be administered only under the control of a medical doctor, and their side effects have also been reported [Hadler A. J.: J. Clin. Pharm., 12, 453(1972); and Stunkar D. A., et al: Lanset, 1, 503(1973)].
As a method which can replace the foregoing impracticable methods, there is an approach to prevention of absorbed aliments from being accumulated as fat, without limiting the ingestion of fat and the like. Dehydroepiandrosteron [Yen T. T., et al: Lipid, 12, 409(1977)] can be mentioned as a medicine for this purpose. However, it has been reported that this medicine entails a side effect whereby the hormonal balance is lost [Baulien E. E., et al.: J. Clin. Endocrinal Metal, 23, 1298(1963); and Siiteri P. K., et al.: Steroid, 2, 713(1963)]. Further, it has been known that the hot-taste component (capsicin) of capsicum is useful for promoting the decomposition of accumulated. body fat [Kawada T., et al: J. Nutr., 116, 1272(1986)]. However, this component has not yet been put to practical use due to its stimulating taste. The use of thyroid hormone may also be considered because it promotes the decomposition of body lipid. However, it has been pointed out that thyroid hormone is poor in lipid specificity, and that this hormone decreases the amount of muscles rather than that of lipid [Kyle L. H., et al: N. Eng. J. Med., 275, 12(1966); and Gray G. A., et al: Am. J. Clin. Nutr., 26, 715(1973)].
An approach to prevention of ingested lipid from being absorbed by the alimentary canal, which is made to overcome the above-described shortcomings, is attracting public attention these days. However, neomycin, which is known as a medicine having the above effect, gives rise to a serious side effect of causing fatty diarrhea [Falcon W. W., et al: Ann. N. Y. Acad. Sci., 132, 879(1966)]. Capsules of a certain type which can trap dietary lipid at an alimentary canal [Japanese Laid-Open Patent Publication No. 52713/1989], crosslinked products of collagen [Specification of U.S. Pat. No. 4,865,850], and capsule preparations containing sodium polyacrylate as an aggregating agent [Japanese Laid-Open Patent publication No. 120227/1991] have been disclosed. However, their effects are still unclear, because, for example, we found that the total amount of discharged lipid was not observed in any of the above disclosures. An oral lipid absorber comprising a crosslinked polymer of long-chained alkyl(meth)acrylate has been proposed as a material having a lipid absorption inhibitory effect [Japanese Laid-Open Patent Publication No. 23136/1993].
In recent years, it has been found that chitosan has a lipid absorption inhibitory effect [Nagyvary J. J.: Nutr. Rep. Int., 20, 677(1979); I. Ikeda: J. Nutr., 119, 1383(1989); and Japanese Laid-Open Patent publication No. 290170/1991], and this effect of chitosan seems to be hopeful. However, in the above studies, the lipid concentration in blood after feeding is adopted as an index, and there are many obscure points in the total balance of lipid. The effects of chitosan of increasing the amount of lipid discharged in the stool and decreasing body lipid, evaluated by using chickens have been reported [Kobayashi, et al: Nihon Kakin Kaishi, 28, 88(1991)]. However, it does not discuss multiplier effects of chitosan and other components.
As described above, various approaches have been made in order to decrease dietary lipid or to reduce body fat, and a variety of materials, commodities and methods have been proposed for this purpose. However, they are not excellent in taste or are harmful to health, so that most of them are abandoned before the purpose is fully attained.